Milking apparatus

ABSTRACT

A milking plant for cows is provided with a milking machine comprising teat cups, which are connected separately to the teats of an animal. The milk obtained from each udder quarter is conveyed through a separate line to a milk measuring device. The milk measuring device includes four milk meters, one for each teat cup, having separate discharge lines coupled to common discharge lines which connect with a circulation line or loop that includes a bulk milk cooling tank, a two-speed or variable speed pump, and a plurality of heat exchangers for precooling the milk received from the common discharge lines before it is received in the bulk milk cooling tank and to recirculate and cool the milk received in the bulk milk cooling tank. After the milk has been discharged from the bulk milk cooling tank and the system is to be disinfected, washed and rinsed, the heat exchangers being used in a heat pump arrangement, can heat the fluid therein as selected and desired for sanitizing the system.

This is a continuation U.S. application Ser. No. 07/818,764, filed Jan.13, 1992, now U.S. Pat. No. 5,195,456 which is a continuation-in-part ofapplication Ser. No. 07/485,579, filed Feb. 27, 1990, which issued asU.S. Pat. No. 5,080,040, on Jan. 14, 1992.

BACKGROUND OF THE INVENTION

The present invention relates to a milking plant for milking cows, whichplant comprises teat cups that are connectable to the respective teatsof a cow's udder, the milk obtained from each udder quarter capable ofbeing conveyed with the aid of the said teat cups, through a separateline to a milk measuring device for measurement and evaluationwherefrom, if from an unhealthy quarter it is separated, otherwise it iscaused to flow through a common milk discharge line into a milkcirculation loop, including a bulk milk tank, wherein the milk is cooledand continuously circulated to maintain it in wholesome condition fordelivery to a dairy.

In prior art milking plants of the above-defined type, the teat cups arecombined in one single milking claw, while the buffer space in themilking claw, to which space the teat cups are connected directly,comprises four separate chambers. Via four separate milk hoses themilking claw is connected to a milk meter, from which the milk can beseparated or be supplied to a milk cooling tank. The object of thefour-quarter milking claw is to provide better means to maintain theudder in a healthy condition; the milk originating from an inflamedquarter has a higher conductivity than that from a healthy one, whichcan be measured for each quarter, whereafter it can be determinedwhether or not the milk must be separated.

Such milking apparatus is less suitable when a common claw is used forall four teat cups from the cow's udder, and therefore it is preferablethat the teat cups be interconnected to the milking system in generalindividually and independently of each other to the teats of the udder.

Moreover, having prevented unwholesome milk from being mixed with thatfrom healthy quarters, it is important that the milk be maintained inits healthy state by being held continuously at the proper cooltemperature (about 3° C. or 38° F.) and sufficiently circulated whileperiodically receiving warm milk from several milkings so that themilk's wholesomeness is maintained until its delivery to a dairy whereinit is further processed and placed in containers for retail sales.

SUMMARY OF THE INVENTION

The object of the invention herein disclosed is to provide a milkingplant which is not only suitable for use when a single milking claw isused, but even more so wherein the teat cups are interconnected into thesystem individually and independently of each other.

According to the invention, the milking plant of the above-defined typeis characterized in that the milk measuring device includes four milkmeters, the separate discharge lines of which are coupled to a commondischarge line leading to a circulation loop that includes a bulk milkcooling tank and a pump for circulating the milk in the circulation loopwhile continuously cooling same. Due to the largely parallel structureof the milking system, an improved method of monitoring milk productionis provided. The milk production can be effected from each udder quarterindividually, while the teat cups can be removed independently of eachother; consequently, the teats are not burdened unnecessarily.

In addition, according to the invention, a milk meter includes a milkreceptacle and a measuring chamber, the milk being caused to flow by avacuum produced in the milk receptacle into the measuring chamber, andthen is caused to flow in defined quantities by means of compressed airfrom the measuring chamber into the relevant, separate discharge line.In particular, according to the invention, the air drawn along by thevacuum together with the milk from the relevant teat cup is separatedtherefrom in the milk meter. Consequently, milk containing air isreceived from the teat cup into the milk meter, whereas it is only themilk that is discharged therefrom to the milk circulation loop includingthe bulk milk cooling tank; in this respect it should be noted that itusually has been the custom to effect the milk-air separation notearlier than in the bulk milk cooling tank. In a specific embodiment inaccordance with the invention, the milk meter is provided with a valverod which, in a first position under a vacuum, leaves the aperturebetween the milk receptacle and the measuring chamber open, and, in asecond position by means of compressed air, closes same. Morespecifically, in accordance with the invention there is provided aswitching element, with the aid of which, in a first switching positionthereof, vacuum is applied to cause the valve rod to be brought to itsfirst position, and, in a second switching position thereof, compressedair is admitted to cause the valve rod to be brought to its secondposition. Furthermore, according to the invention, the measuring chamberis provided with a milk level sensor, which senses when a definedquantity of milk is contained therein and then produces a control signalto cause the switching element to be adjusted from its first position toits second position. Also, in accordance with the invention, theswitching element may be adjusted from its second position to its firstposition after a fixed period of time. However, this might also beeffected by means of a sensor which senses that all of the milk has beenpumped from the measuring chamber, or by means of a flow sensor providedin the line beyond a teat cup. Furthermore, according to the invention,each time when a defined quantity of milk has been established in themeasuring chamber, the milk level sensor may produce a control signalintended for a computer, in which the quantity of milk obtained fromeach udder quarter is recorded for each individual cow. In particular,the recording of this quantity and hence also that of the total quantityof milk obtained from each cow per unit of time, e.g., per day, may bekept on the basis of a progressive average calculated over a definednumber of days.

According to the invention, the measuring chamber, when empty, is closedby a spherical body. Preferably, this spherical body is of such a designthat, when the milk flows from the milk receptacle into the measuringchamber, it floats on the milk contained therein. Thus, each time themeasuring chamber contains a predetermined quantity of milk, it isremoved therefrom by means of the compressed air admitted into thechamber for that purpose. Furthermore, according to the invention, anon-return valve is included in the separate discharge pipe beyond theaperture in the measuring chamber, which aperture can be closed by thespherical body. Via this non-return valve the milk is passed from themeasuring chamber, but only under the influence of compressed air. Inthe opposite direction, the non-return valve prevents reverse milk flow,which might be possible should the pressure in the relevant dischargepipes exceed that prevailing in the measuring chamber. This situation isconceivable because the milk is discharged from four milk meters to thecirculation loop that includes the bulk milk cooling tank through thesame common discharge line. The presence of the non-return valve beyondthe measuring chamber aperture that is closable by the spherical bodyimplies that, during the milking operation, the first obtained milkfills the separate discharge pipe between the said aperture and thenon-return valve, as a result of which, according to the invention, eachtime a cow is milked, the measured quantity of milk recorded by acomputer is numerically increased only once by the known quantity ofmilk corresponding to the volume of the separate discharge pipe betweenthe measuring chamber aperture that is closable by the spherical bodyand the non-return valve.

In order to ensure the admission of compressed air via the measuringchamber into the discharge lines, in particular when these lines must becleared of milk thereby e.g. in connection with a subsequentdisinfecting, washing and rinsing procedure, in accordance with theinvention, the milk meter is provided with a solenoid device which, bymoving the spherical body, has for its object to establish a connectionbetween the closed measuring chamber and the discharge lines.

According to the invention, each milk meter of the milk measuring deviceis provided with a milk conductivity sensor. More particularly, the milkconductivity sensor is arranged in the measuring chamber of a milkmeter. The conductivity of the milk indicates the health of the udderquarter involved, the milk originating from an inflamed quarter having ahigher conductivity than that from a healthy one. The milk originatingfrom an inflamed quarter should not be mixed with the rest of the milk.According to the invention, a separate discharge line is provided with athree-way valve, through which the milk discharged from a relevant milkmeter is either diverted into the common discharge line or, upondetermining that the milk originates from an inflamed quarter, into areceptacle specially provided for the purpose. This three-way valve maybe operated automatically as soon as a relevant milk conductivity sensorhas measured a conductivity which exceeds a preset fixed value. In apreferred embodiment in accordance with the invention, however, the milkconductivity sensor applies a control signal to a computer, in which itis determined whether or not the relevant milk originates from aninflamed quarter, after which, when the former appears to be the case,the computer supplies a control signal to the three-way valve in therelevant separate discharge line so that the milk in question isdiverted to the receptacle. The conductivity of the milk from theindividual quarters can be compared with each other in the computer,whereby it is possible to establish from the spread in the conductivityvalues whether or not there may be a potential inflammation of one ofthe quarters. Older cows and cows in late lactation inherently have ahigher milk conductivity than a younger and freshly calved ones. It istherefore not advisable to compare deviations in conductivity to apreset fixed value, but rather to compare the deviations relative to thecow's own standard, i.e., to compare the conductivity in the computerwith a progressive average determined over a number of days for therelevant cow. The calculation of the progressive average may, of course,be combined with the aforementioned calculation of the spread.

According to the invention, a milk meter is provided with a tube stopvalve, with the aid of which the vacuum connection of the milk meter canbe closed after milking. The end of the milking procedure can bedetected by means of sensors, e.g., with the aid of a milk flow sensorwhich may be incorporated in the line between the teat cup and the milkmeter or in the milk meter itself, or with the aid of the aforementionedmilk level sensor. In accordance with the invention, it is likewisepossible to activate the tube stop valve after a milking period of aduration which is computer defined, e.g., on the basis of the number oftimes the measuring chamber has been emptied, has ended, i.e., byapplying thereto a control signal provided by the computer. In aspecific embodiment, the tube stop valve includes a lifting mechanism toallow air to flow into the milk meter simultaneously with or immediatelyafter closure of the vacuum connection of the measuring chamber. Thiscan be effected with a certain amount of overpressure; a simpler methodis to operate the lifting mechanism, in accordance with the invention,by a valve in the outer wall of the milk meter. The tube stop valve inaccordance with the invention renders it possible, in a simple manner,to remove the vacuum in a teat cup before the teat cup is removed fromthe teat or drops therefrom.

The milking plant is provided in customary manner with a vacuum pumphaving a vacuum balance tank to increase the vacuum stability. Forlarger plants in particular, preferably, the pump and the balance tankare arranged remote from each other and the balance tank is positionedclose to the milking parlor. The balance tank has a plurality of vacuumconnections: for each milk measuring device there are four connectionsfor the vacuum connection of the individual milk meters, fourconnections for the valve rod control in each milk meter, and aconnection for a electronic pulsator system for the four teat cups. Aseparate pulsator may be provided for each teat cup. The suction-restratio in the pulsator system may be adjustable, i.e., that for the rearquarters may be adjusted independently of that for the front quarters.According to the invention, the suction-rest ratio is established by acomputer depending on the milk flow. When the milk flow decreases, itwill be possible to provide a comparatively longer rest. Thiscontributes to a reduction in the burdening of the teats, which is ofthe utmost importance when the animal is milked several times a day.According to the invention, a throttle ring is included in the vacuumconnection from the balance tank to the milk meter. This ring prevents,should one of the teat cups fall from the teat, fluctuations fromoccurring in the prevailing vacuum and more particularly in the vacuumin the other teat cups. For the purpose of ascertaining whether or not avacuum is present in a milk meter, in accordance with the invention, anair flow sensor is provided in the vacuum connection between thethrottle ring and the milk meter.

In the situation wherein the four teat cups are incorporated in onesingle milking claw, the claw housing, whether or not divided into fourcompartments, constitutes a buffer space for the milk transport and forcounteracting fluctuations in the vacuum under the teats to which theteat cups are connected. To obtain the same result in the situationwherein the teat cups are not incorporated in one single milking claw,but are connected to an associated milk meter which is in a relativelymore remote position, in accordance with the invention, each teat cup isprovided with such a buffer space at its lower end. In particular, thisbuffer space for the milk transport is in connection with the outer airvia an air suction aperture. In connecting the teat cups, it isoptionally possible, in order to facilitate this connection, to employan increased vacuum, although in that case more air is drawn into theteat cup.

It must be possible for the milk line system to be thoroughly cleansedand rinsed after milking. In accordance with the invention, for thispurpose there is included in the common discharge line a three-wayvalve, through which in a first position thereof the milk is passed viathe common discharge line to the milk cooling tank, whereas in itssecond position the three-way valve establishes a wash/rinse linesystem. In particular, the wash/rinse line system includes a rinsejetter which, with the object of flushing the lines, is connected to ateat cup, while a washing and/or rinsing fluid is passed by the vacuumin a milk meter from a washing and/or rinsing fluid container through afirst rinsing line to the wash/rinse jetter and from there, via a teatcup, into the relevant milk meter, whereafter the washing and/or rinsingfluid is returned through the relevant separate discharge line, thecommon discharge line, the three-way valve incorporated therein, and asecond washing and/or rinsing line to the washing and/or rinsing fluidcontainer. Prior to washing and/or rinsing operations, all the milk mustfirst have been forced from the lines to be washed and/or rinsed, inparticular all the milk present in the common discharge line must havebeen forced through the three-way valve incorporated therein. Todetermine that this has indeed occurred, according to the invention, anair-milk sensor is provided in the common discharge line in front of thethree-way valve incorporated therein.

Furthermore, in accordance with the invention, a heat exchanger may beprovided in the common discharge line forward of the three-way valveincorporated therein as a pre-cooling device for the bulk milk coolingtank.

Also, in accordance with the invention, the bulk milk cooling tank isincluded in the circulation line, to which the common discharge lines ofthe individual milk meters are connected. More generally, therefore, theinvention relates to a milk measuring system for milking cows, whichsystem comprises a milk cooling tank, characterized in that this milkcooling tank is included in a circulation line or loop, the commondischarge lines of the individual milk meters being connected to thesaid circulation line. For the purpose of preventing, after milking,that residual milk remains in the circulation line, in accordance withthe invention, in the circulation line is provided with a pump to pumpthe milk from the bulk milk cooling tank therethrough. Preferably, thecirculation line or loop is thermally insulated and includes means forcooling the milk flowing therethrough whereby the provision of coolingcoils or plates for the bulk milk cooling tank can be reduced orentirely eliminated. With the milk being circulated from and through thebulk milk cooling tank, milk inside the tank is kept in motion and it isno longer necessary to provide other means such as a stirrer, foraccomplishing the same function.

In a preferred embodiment in accordance with the invention, the bulkmilk cooling tank is provided with a washing and/or rinsing fluid supplyline, through which, after all the milk has been removed from the bulkmilk cooling tank, a washing and/or rinsing fluid is introduced into thebulk milk cooling tank, which washing and/or rinsing fluid is circulatedthrough the circulation line by means of the pump. In particular, thepump has the capacity to operate at at least two speeds, that is, thepump may have two more operating speeds, or may be a variable speedpump. Milk therein is circulated at a relatively low speed whereas thewashing and/or rinsing fluid is circulated at a relatively high speed.Furthermore, in accordance with the invention, a three-way valve isincorporated in the circulation line, by means of which the circulatingwashing and/or rinsing fluid can be discharged. To wash and/or rinse thebulk milk cooling tank in a most advantageous manner, in accordance withthe invention, it includes a sprayer connected to the washing and/orrinsing fluid supply line; by mounting this sprayer to be movable, sothat the entire inner surface of the bulk milk cooling tank can besprayed and cleaned, an extremely efficient cleansing and rinsing systemis provided.

For a better understanding of the invention and to show how the same maybe carried into effect, reference will now be made, by way of example,to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematically an arrangement of a milking plant for milkingcows;

FIG. 2 diagrammatically shows a basic arrangement of the milking plantin accordance with the invention;

FIG. 3 is a more detailed representation of the basic structure of amilk meter in the arrangement shown in FIG. 2;

FIG. 4 is a more detailed representation of the basic structure of ateat cup in the arrangement shown in FIG. 2;

FIG. 5 is a schematic representation of a cooling loop used for coolingmilk entering and which is circulated through the bulk milk tank as partof the loop;

FIG. 6 is a fragmentary view of an evaporator structure for the coolingloop conduits; and

FIG. 7 is a sectional view taken on lines VII--VII of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic arrangement of a milking plant for milkingcows, wherein only two milking stations are shown by way ofillustration, a cow being present in each. Corresponding components inthe drawings have been denoted by the same reference numerals. For eachmilking station, a milking robot 1 designated generally by referencenumber is provided which includes at one end a set of four teat cups 2.The invention, as such, is generally independent of the manner in whichthe teat cups are connected; the teat cups may, combined in one singlemilking claw, be connected together as well as individually andindependently of each other to respective teats of a cow's udder. Themilk obtained from each udder quarter with the aid of teat cups 2 can beconveyed through a separate line 3 (FIGS. 2, 3 and 4) to a milkmeasuring device 4. Milk measuring devices 4 of the various milkingstations are interconnected to a milk recirculation line or loop 5 thatincludes a bulk milk cooling tank 6.

Milk measuring device 4 comprises four milk meters 7, only one of whichis shown in FIG. 2. FIG. 2 furthermore illustrates the basic arrangementof the milking plant, only one teat cup 2 and only one milk meter 7being shown, however, in this arrangement for the sake of simplicity.The individual discharge lines 8 of milk meters 7 of each milkingstation are coupled to a common discharge line 9 which leads to therecirculation line 5 and, via line 5, to bulk milk cooling tank 6, whichis included as part of the loop comprising line 5. FIG. 3 is a moredetailed representation of the structure of milk meter 7 incorporated inthe milking plant shown in FIG. 2. It will thus be seen that milk meter7 includes a milk receptacle 10 and a measuring chamber 11, in whichconnection the milk flows under a vacuum produced in milk receptacle 10through separate line 3 connected to teat cup 2 into measuring chamber11 and is pumped in defined quantities by means of compressed air fromthe measuring chamber 11 into separate discharge line 8. Milk meter 7includes a valve rod 12 which, in a first (shown) position under avacuum, causes an aperture 13 between the milk receptacle 10 and themeasuring chamber 11 to be in an opened condition, and, in a second (notshown) position by means of compressed air, closes aperture 13. At itsupper side, the milk meter includes a chamber 14, in which chamber valverod 12 comprises a piston 15. Valve rod 12 is capable of upward anddownward movement in and through this chamber 14. In the space below thepiston 15 there is provided in the wall of the chamber 14 an aperture16. Via such aperture 16, milk meter 7 is connected to a switchingelement 17 (see FIG. 2). In a first position of switching element 17, avacuum is applied to cause the valve rod 12 and the piston 15 to bemoved downwardly to its opened first position. In a second position ofswitching element 17, compressed air is admitted into the space belowthe piston 15 to cause the valve rod 12 and therefore the piston 15 tobe moved upwardly to its closed second position, thereby closing theaperture 13. Milk meter 7 furthermore includes a tube 18 which, viarelatively narrow apertures 19 and 20, is connected to the space in thechamber 14 below the piston and to measuring chamber 11 via aperture 19,tube 18 and aperture 20, as a result of which the milk present in themeasuring chamber 11 is passed into the separate discharge line 8.

Measuring chamber 11 is provided with a milk level sensor 21, by meansof which it is determined when a defined quantity of milk is containedtherein. When the milk level in measuring chamber 11 reaches that of thesensor 21, sensor 21 provides a control signal S1 (see FIG. 2) to causeswitching element 17 to be adjusted from its first position to itssecond position, so that measuring chamber 11 is emptied. After a fixedperiod of time, switching element 17 is adjusted from its secondposition to its first position; this period of time is of such durationthat there is sufficient time for measuring chamber 11 to be emptied.When the switching element 17 has returned to its first position, themeasuring chamber 11 is filled again. Milk level sensor 21 also has thecapacity for providing a control signal S2 to a computer 22, in whichthe quantity of milk obtained from each udder quarter is recorded foreach individual cow.

In the lower part of measuring chamber 11, a spherical body 23 isprovided. When measuring chamber 11 is empty, this spherical body 23closes an aperture 24 between measuring chamber 11 and separatedischarge line 8. Spherical body 23 is composed of a material of lowspecific gravity or is constructed to be hollow so that, when milk flowsfrom milk receptacle 10 into the measuring chamber 11, body 23 floats onthe milk contained therein. When the milk is forced from the measuringchamber 11 into separate discharge line 8, aperture 24 is closedautomatically by spherical body 23 once measuring chamber 11 is empty. Anon-return valve 25 (FIG. 2) is arranged in separate discharge line 8downstream from aperture 24 that is located in measuring chamber 7,preferably as closely as possible therebeyond. Via this non-return valve25, the milk is allowed to pass from measuring chamber 11, but only whenunder the influence of compressed air. In the opposite direction,non-return valve 25 blocks any milk flow which might be possible if, forwhatever reason, the pressure in the relevant discharge lines shouldexceed that prevailing in measuring chamber 11 in front of non-returnvalve 25. When, during the milking operation, the first obtained milkflows into measuring chamber 11, then not only is measuring chamber 11itself filled, but also the space in the separate discharge line 8between the non-return valve 25 and said aperture 24 is filled. By eachsubsequent pump stroke, however, only that milk contained in themeasuring chamber is drawn off, so that the total quantity of milk asdetermined by the computer during milking for each udder quarter must beincreased initially once by the quantity of milk that corresponds to thevolume of separate discharge line 8 between non-return valve 25 and saidaperture 24. This is, however, a constant correction to be entered intothe computer 22 on recording of the quantity of milk obtained. Aftermilking, the milk must also be removed from separate discharge lines 8and common discharge line 9, whereupon it is received in circulationline 5 and bulk milk tank 6. For that purpose, aperture 24 in measuringchamber 11 should be opened to allow compressed air in chamber 11 toflow therefrom. To that end, milk meter 7 is fitted with a solenoiddevice 26 which moves spherical body 23 upwardly in response to acontrol signal S3 from computer 22.

Milk meter 7 includes a milk conductivity sensor 27, which sensor ispreferably arranged in measuring chamber 11. A control signal S4 frommilk conductivity sensor 27 provides a measure of the udder's conditionof health; in the case of mastitis, the electrical conductivity of themilk is higher than that of milk obtained from a healthy udder or from ahealthy udder quarter. The milk originating from an inflamed udderquarter must be segregated from the milk from healthy udder quarters.For this purpose, separate discharge line 8 is provided with a three-wayvalve 28 (FIG. 2), through which the milk pumped from the milk meter 7is either passed into the common discharge line 9 or, after it has beenfound that the milk originates from an inflamed quarter, into areceptacle 29 specially provided for the purpose. Three-way valve 28might be operated automatically as soon as signal S4 produced by themilk conductivity sensor 27 indicates a value which exceeds a presetvalue. It is, however, more advantageous to apply the control signal S4computer 22 which, taking account of the further conditions of thespecific cow, generates a control signal S5, by means of which thethree-way valve 28 can be operated.

In addition, milk meter 7 is provided with a tube stop valve 30, withthe aid of which the vacuum connection 31 can be disconnected from themilk meter after milking. During milking, a vacuum prevails in the milkreceptacle 10. After the milking procedure has ended, the vacuum must beremoved, and it is not until then that the teat cups are removed fromthe teats. Prior to removing the vacuum from milk receptacle 10, vacuumline 31 must first be closed. For that purpose, after a milking periodpreset in the computer 22 has elapsed, a control signal S6 is applied tothe electromagnet 32 of tube stop valve 30. By means of the then ismoved upwardly to seal the vacuum connection 31 energized electromagnet32, a rod 33 having a spherical end 34 against the fixed stop 35. Withthe aid of a lifting mechanism 36 which is connected pivotably to therod 33, a valve 37 in the wall of the milk receptacle 10 is drawnupwards simultaneously, as a result of which air can flow freelythereinto.

The milking plant as shown schematically in FIG. 2 includes in acustomary manner a vacuum pump 38 having a vacuum balance tank 39 toincrease the vacuum stability. Balance tank 39 has a plurality of vacuumconnections. A vacuum connection 31 is provided for milk receptacle 10of each milk meter 7. A vacuum connection 40 is present for eachswitching element 17. In addition, a vacuum connection 41 is providedfor an electronic pulsator system 42 for the four teat cups. A throttlering 43 is provided in vacuum connection 31 to prevent vacuumfluctuations in the various milk meters because one of the teat cups isdislodged or otherwise removed from its corresponding teat. To ascertainwhether or not a vacuum is present in the milk meter, an air flow sensor44 is arranged in the vacuum connection between throttle ring 43 and therelevant milk meter, which sensor supplies computer 22 with a controlsignal S8 indicating the presence of vacuum in the line 31. Hereby thissignal also provides an indication whether the teat cups are connectedcorrectly.

FIG. 4 shows a longitudinal cross-sectional view of a teat cup 2; thisteat cup in a customary manner has a solid, e.g., metal, sleeve 45, aninner wall 46 made of a flexible material, e.g., rubber, enclosedthereby, and a rubber cap 47 which seals the space between sleeve 45 andinner wall 46 at the upper side. At the lower side, the space betweensleeve 45 and inner wall 46 is sealed by a sealing ring 48, while atsome distance thereabove there is provided between the sleeve 45 and theinner wall 46 a ring 49 having an aperture 50. Between sealing ring 48and ring 49 there is located a space, in which the electronic pulsatorsystem 42 produced through the line 52 and via an aperture 51 apulsating vacuum, thereby effecting in the space between sleeve 45 andinner wall 46 sufficient pressure to close the inner wall firmly aroundthe teat, when the teat cup is connected thereto, or sufficient vacuumto cause the inner wall to move outward again, whereby a rhythmicmovement is provided around the teat as required for the milkingoperation to be performed. To function as a buffer for the milk to becollected and to minimize the fluctuations in the vacuum under the teat,there is provided in the lower part of teat cup 2 a buffer space 53, inwhich a relatively narrow bleeder opening or air suction aperture 54 ismade for the milk transport. Line 3, intended for the discharge of themilk to milk meter 7, is connected to this buffer space 53. In addition,buffer space 53 contains a fixed element 55, which element partlyprojects into the aperture between the teat space and the buffer space53 to ensure that milk flows gradually into the buffer space 53 and asplitting of the milk is prevented. At the upper end of the fixedelement 55 a sensor can be provided to measure temperature. Thetemperature of the milk indicates the body temperature of the cows beingmilked; such temperature being above normal for cows in heat and sickcows.

When the milking operation has been completed, an arrangement isprovided for cleaning and rinsing the milk line system. To such end, arinse line system is provided constituted by a rinse fluid container 56having a valve 57, a first rinse line 58, a rinse jetter 59 which can befitted around the end of the teat cup 2 in a fluid-tight manner, teatcup 2, line 3, milk meter 7, separate discharge line 8, common dischargeline 9, a three-way valve 60 incorporated therein and a second rinseline 61. In its first position, three-way valve 60 admits milk from thecommon discharge line 9 into circular line 5, and, in its secondposition, cleansing and/or rinse fluid from common line 9 flows into thesecond rinse line 61. Valve 60 also, of course, includes a closedposition to prevent fluid flow either to rinse line 61 or to tank 6.After the milking, a washing and/or rinse command can be delivered bycomputer 22 which, to that end, applies a control signal S7 to three-wayvalve 60 to adjust same to the appropriate position. Prior to startingthe cleansing and rinsing steps after the milking operation has ended,the discharge lines must first be freed from milk. This is effected bypassing compressed air through each measuring chamber 11, as a result ofwhich the spherical body 23 therein is pushed upwardly and the aperture24 is opened. Forward of the three-way valve 60, incorporated in commondischarge line 9, is an air-milk sensor 62, which sensor sends a controlsignal S9 to the computer, on the basis of which control signal thecomputer can establish when there is no longer any milk present in thecommon line--compressed air then being sensed by the air-milk sensor 62instead of milk--so that the valve 60 can be adjusted to prevent theflow of the compressed air therethrough into the bulk milk cooling tank6 and to be ready for initiating the washing and rinsing procedure. Dueto the vacuum in the milk receptacle 10, cleansing and/or rinse fluid isdrawn from the rinse fluid container 56 through first rinse line 58,rinse jetter 59, teat cup 2 and line 3 to milk receptacle 10, from whereit flows into measuring chamber 11. Thereafter it is pumped from chamber11 in the same manner as the milk and is fed back via the separatedischarge line 8, the common discharge line 9, the three-way valve 60and the second rinse line 61 to the rinse fluid container 56.

In common discharge line 9 there is arranged before three-way valve 60,which is incorporated therein, a heat exchanger 63 as a pre-cooler forthe milk cooling tank.

Bulk milk cooling tank 6 is included in the loop comprising circulationline 5, to which, via relevant three-way valves 60, common dischargelines 9, of individual milk meters 7 are connected. A pump 64 is alsoincorporated in circulation line 5. Pump 64 is capable of operating atat least two different speeds. To keep the milk in motion and to preventmilk residues from being deposited in the circular line 5, the milk iscirculated at a relatively low speed from bulk milk cooling tank 6through circulation line 5. Preferably, in this connection, circulationline 5 is thermally insulated. Usually, bulk milk cooling tank 6 isemptied several times a week, whereafter it is washed and/or rinsed. Acleansing and/or rinsing fluid is introduced into that tank 6 via avalve 65 and a spray nozzle 66. When spray nozzle 66 is arranged so asto be capable of moving, it jet cleans and rinses the entire innersurface tank 6. The cleansing and/or rinsing fluid is circulated by thepump in the circulation line at a relatively high speed and isultimately discharged via a three-way valve 67. Also here, valves 65,67, spray nozzle 66, and pump 64 can be controlled from the computer 22.

Although in FIG. 2 they are shown as being single, the several elementsare provided fourfold for each milking device; in particular this holdsfor the rinse jetters, the teat cups and the milk meters, as well as forthe lines connected thereto and the elements incorporated therein(valves and sensors). Preferably, however, the four milk meters arecombined into a single and integral milk measuring device.

A further embodiment of the invention is disclosed with reference toFIGS. 5, 6 and 7 for utilizing the loop or circulation line 5 forcooling the milk which enters into the bulk milk tank 6 and forcontinuously cooling the milk previously received in tank 6. Automaticmilking, the bulk milk tank system and automatic cleaning of the milkingapparatus have been revolutionary advances in the dairy farm art. Cowsare now conventionally milked twice a day with the milk leaving thecows' teats at approximately 90° F., whereupon it is conveyed throughstainless steel conduits to the stainless steel bulk milk tank.Conventionally, the milk may be cooled by precoolers before it isreceived by the bulk cooling milk tank as disclosed in the firstembodiment and, in any event, the bulk cooling milk tank includes in itssides plates or coils for evaporative cooling. The tanks are also wellinsulated to ensure that the milk stored therein will be maintained atthe proper temperature, usually about 38° F. Because milk leaving thecow's teats is much warmer, usually on the order of about 90° F., milkprecoolers are frequently utilized and improve the efficiency of thesystem. Depending upon the type of precooler used, cleaning and rinsingcan sometimes be a serious problem which must be accomplished largelymanually to ensure thorough cleaning as well as to be able to inspectall parts of the precooler to which the milk may be exposed. Bulkcooling milk tanks are produced in a variety of different sizesdepending upon the volume of milk which is produced by the dairy farm'sherd wherein they are installed. Two or more tanks may be used at asingle installation although, for economy reasons, most installationswill have only one tank. At most installations, the temperature of themilk within the bulk milk tank is continuously monitored to ensure thatit does not rise above a certain temperature, which is usually about 50°F. It is also necessary that the milk be stirred to ensure that thetemperature of the milk within the bulk milk tank is uniform throughout.The present invention of the instant embodiment provides not only forthe precooling of the milk as it proceeds from the milking apparatusinto the bulk milk tank, but also the invention provides for thecontinuous cooling of the milk in the bulk milk tank and maintaining auniform temperature thereof without the need of a stirrer. Moreover, inmany cases the necessity of providing evaporative coils in the bulk milktank is eliminated inasmuch as the circulation of the milk through therefrigerated circulation loop may sufficiently cool the milk to maintainit at a temperature which is sufficiently low that the milk can bestored for a lengthy period of time without serious or significantdeterioration of its quality.

The concept of precooling the milk via the piping between the individualmilking units and the bulk milk tank is known as exemplified by U.S.Pat. No. 4,013,043, of Mar. 22, 1977, to Kirwan. However, this systemutilizes water jackets which are applied over the milk conduits for themajor portion of their lengths, whereby the cooling is accomplished bycold water. But water cooling is not necessarily overly efficientbecause it does not involve a phase change as occurs with normalrefrigeration. Phase changes in the condensers and evaporators ofconventional refrigeration units take advantage of the latent heat whichis released from the refrigerants during the condensation andevaporation phase changes. Accordingly, considerable improvement in theheat transfer from refrigerants confined within jackets surrounding themilk conduits can be obtained through the use of conventionalrefrigerants within the jacketed spaces surrounding the conduits thatperform the evaporative function of a conventional refrigerationapparatus. Through the utilization of such jackets on the loopcomprising circulation line 5, one obtains not only the advantages ofprecooling the milk before it is received in the bulk milk tank 6, butalso of continuously cooling the milk by circulating same around theloop between and even during the milking operations when milk iscontained in the bulk milk tank 6. This also "stirs" the milk tomaintain the milk generally homogeneous in character both from thestandpoint of temperature and also in precluding separation of thevarious milk constituents. This system further permits a reduction oreven elimination of the evaporator coils which are conventionallyinstalled in bulk milk tanks.

As mentioned above, the jacketing the conduits between the automaticmilking devices and the bulk milk tank wherein cold water is utilized asa cooling medium is not unknown and is disclosed, for example, in U.S.Pat. No. 4,013,043, of P. Kirwan, of Mar. 22, 1977. Further, U.S. Pat.No. Re. 23,544, of Duncan, of Sep. 2, 1952, discloses the use of anevaporator in a cylindrical unit surrounding a milk line or hose leadingto a milk can. Accordingly, the concept of cooling milk while flowing inthe conduit from the milking device to a milk storage container fromwhence it is delivered to the dairy is, at least in a broad sense, knownin the prior art. An object of the embodiment shown in FIGS. 5-7 is toprovide in a milking plant, a recirculation line which receives thecommon discharge lines of the individual milk meters and wherein themilk delivered to the bulk milk cooling tank is precooled and thereaftercirculated and simultaneously cooled to maintain the milk in ahomogeneous state and at low temperature for several milkings, wherebythe milk will be of an excellent quality and purity upon beingtransferred to the milk transport tank truck and received at the dairy.Further, inasmuch as refrigeration apparatus can readily incorporateand, in fact, constitute a heat pump, the same milk conduit lines whichwere cooled during the milking operations and while the milk was beingcirculated therein can next, for the purpose of washing, disinfecting,and rinsing those conduits, be heated to maximize the sanitizing effectsof this operation.

Referring now to FIGS. 5-7, reference numeral 5 designates generally theloop comprising the circular line or conduit which receives the commondischarge lines 9 leading from the four discharge lines 8 that receivemilk from individual teat cups 2 and milk meter 7 as previouslydescribed. Between the receipt of each discharge line 9 and the bulkmilk cooling tank 6, and also throughout the loop 5, there aresurrounding the conduit of loop 5, a plurality of evaporator/condensers70 which serve to cool milk flowing in conduit loop 5 during the milkingoperation and between milking operations while milk from prior milkingoperations is stored within the bulk milk cooling tank 6.Evaporator/condensers 70 can also be used to heat disinfectant, washingand rinsing fluids which are passed therethrough during the cleansingportion of the operation which is initiated after the bulk milk coolingtank 6 has discharged its contents to the milk transport tank truck,which generally occurs every other day or at intervals of not more thantwo or three days. Where a milking parlor, as such, is involved,normally there will only be two common discharge lines 9 from twomilking stations which are received in the circular loop 5. However,with a stanchion barn operation, it will be understood that a largenumber of such common discharge lines will be involved. Theevaporators/condensers 70 each comprise a jacket member 71. Jacketmember 71 is constructed to have six inwardly extending fins or dividers72 and 74 which are integral with, or in any event provided with anefficient thermal connection with, conduit 5. A ring member 75 is weldedto close each end of jacket members 71 in a manner wherein it is weldedboth to conduit 5 and to each jacket member 71. Two of the dividermembers 74 are inset at one end away from ring member 75, but are flushtherewith at the other end. The other four dividers members 72 are flushwith ring member 75 at the end shown in FIG. 6 and inset therefrom atthe opposite end from the corresponding opposite ring member 75. Eachjacket member 71 has an inlet connection 76 and an outlet connection 77for the evaporation phase. In the condensing phase, outlet 77 thenbecomes inlet whereas inlet 76 functions at an outlet. In either case,an elongated sinuous pathway is defined by the dividers 72 and 74. Thus,in the evaporation phase, refrigerant, as a liquid, first enters throughinlet 76, travels horizontally through a space defined by the two lowerdividers 72, to the end of the jacket member 71, wherein it turns aroundthe inset portions of the lower dividers 72 and enters into the furtherhorizontal spaces defined by the lower dividers 72 and the dividers 74.The refrigerant again, as it is evaporated by the warm milk flowingthrough conduit 5, undergoes a phase change from a liquid into a gas,and flows around the inset ends of dividers 74, again through thehorizontal passageways defined by the intermediate dividers 74 and theupper dividers 72, whereupon at the end thereof it reverses course andis drawn out through the space defined by upper dividers 72 into theoutlet 74. In the condenser phase, a hot gas enters in the now inlet 77to follow then a reverse fluid flow, wherein it is condensed and itslatent heat of condensation is transferred to the liquids used fordisinfection, washing, and rinsing now flowing through conduit 5. Pump74 is, as previously described, kept at a relatively slow speed forcirculating milk through the loop 5, is now operated at a higher speedfor the disinfecting, washing and rinsing operations. Although notshown, it will be appreciated that the evaporator/condenser 70 as wellas the conduit 5 are normally insulated to minimize any significantlosses or gains of thermal energy from the ambient air.

Although we have disclosed our preferred embodiments of the invention,it should be understood that it is capable of other adaptations andmodifications within the scope of the appended claims. For example,various types of refrigerant and heat pump apparatus may be utilizedwith the invention, including not only those which use conventionalfluorocarbon refrigerants, but also other refrigerants which arecompatible with the metal or metals or other materials of which theevaporator/condensers are constructed. These include water and waterbased mixtures which can be utilized as a refrigerants at low absolutepressure and are quite advantageous because of water's high specificheats that permit a considerable transfer of thermal energy during itsevaporated and condensation. Water and appropriate water based mixturesare also highly desirable because of their lack of toxicity or potentialto cause environmental harm. To ensure that flow from the commondischarge lines 9 is not impeded by circulation in loop 5, theirconnections with loop 5 may use well known structures which takeadvantage of the Bernoulli effect, that is the phenomenon of internalpressure reduction with increased stream velocity in the fluid so, ineffect, milk is drawn from line 9 into conduit 5. To ensure drainage,the conduit 5 may be supported in a manner wherein it is at a minordeviation from horizontal, say 3°-7°. To the extent that suitablematerials permit same, evaporators/condensers 70 may constitute in largepart extrusions to the extent possible. In addition, it is contemplatedthat the computer control will be utilized to the maximum extentpractical and feasible to provide the necessary automatic control tomaintain operations of the milking plant disclosed herein at their mostadvantageous effectiveness and efficiency to ensure that the operationproduces and delivers to the dairy only the highest quality product.Although indicated herein that the pump 64 is a two speed pump, a slowerspeed for the recirculation and cooling operations and a higher speedfor the disinfecting, washing and rinsing operations, it will beappreciated that pump 64 may also be a variable speed pump which isadvantageous in some instances during the milking operation to controlthe mixing ratios of the already cooled milk with the much warmer milkreceived directly from the dairy cows so that the milk within the bulkmilk cooling tank 6 is at all relevant times maintained at a desirablylow temperature.

Having disclosed our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:
 1. A milking tank formilking cows comprising a plurality of automatic milkers, a separate amilk discharge line from each of said milkers, a milk conduit line loopinto which each of said milk discharge lines is interconnected todeliver milk thereto from the corresponding said automatic milker, acommon milk discharge line interconnecting said separate milk dischargelines with said milk conduit line loop, said milk conduit line loopcomprising a bulk milk tank and a milk pump whereby milk can becirculated by said pump around said loop, including through said bulkmilk tank, a valve in said common milk discharge line which is providedwith a first position for passing milk flowing through said common milkdischarge line to said milk conduit line loop and a second position forpassing washing and rinsing fluids of a wash and rinse system throughsaid common milk discharge line and said milk discharge lines.
 2. Amilking plant in accordance with claim 1, wherein said pump has at leasttwo speeds comprising a slower speed for continuously circulating saidmilk in said loop and a faster speed for circulating cleansing andrinsing fluids through said loop, including said bulk milk tank, forwashing and rinsing the interiors of the conduits that comprise saidloop and said bulk milk tank therein after said milk has been dischargedfrom said bulk milk tank for delivery to a dairy.
 3. A milking plant formilking cows that comprises a plurality of automatic milkers, a bulkmilk tank, means for circulating milk into and out of said bulk milktank, separate discharge lines from said plurality of automatic milkersinterconnected into said milk circulation means, a milk circulation loopthat includes said milk circulation means, said bulk milk tank beingincluded in said milk circulation loop in an arrangement wherein milkcan be continuously circulated around said milk circulation loopincluding through said bulk milk tank and said milk circulation means, apump in said milk circulation loop for circulating milk through saidmilk circulation loop, conduit means for conveying milk received fromsaid automatic milkers to said bulk milk tank, said conduit meanscomprising said separate discharge lines and said milk circulation loop,a valve in said conduit means, a wash and rinse system operativelyconnected to said valve, whereby when said valve is in a first position,a fluid passage is provided for milk received by said automatic milkersto flow through said conduit means to be received in said bulk milktank, and when said valve is in a second position, a passage is providedfor washing and rinsing fluids to be received from said wash and rinsesystem in said conduit means for flushing and cleaning milk and milkproduced residues therefrom.
 4. A milking plant for milking cows,comprising teat cups which are connectible to the respective teats of acow's udder, a bulk milk cooling tank, conduit means for conveying milkreceived in said teat cups to said bulk milk cooling tank, a commondischarge line in said conduit means, a valve in said common dischargeline, a wash and rinse system operatively connected to said valve,whereby when said valve is in a first position, a passage is providedfor milk received in said teat cups to flow through said conduit meansand be received in said bulk milk cooling tank, and when said valve isin a second position, a passage is provided for washing and rinsingfluids to be received from said wash and rinse system in said conduitmeans for flushing milk and milk residues therefrom.
 5. A milking plantin accordance with claim 4, wherein said wash and rinse system includesrinse jetters which are connectible to said teat cups, a first rinseline in said wash and rinse system operatively connected to said rinsejetters, a second rinse line in said wash and rinse system lineoperatively connected to said valve, whereby a passage is provided insaid wash and rinse system for introducing wash and rinse fluid intoeach of said teat cups via said rinse jetters and for the flow therefromthrough said conduit means to said valve and from said valve throughsaid second rinse line.
 6. A milking plant in accordance with claim 5,wherein said wash and rinse system comprises a fluid container, saidfluid container being connected to each of said rinse jetters to providewash and rinse fluid thereto, and said second rinse line connected tosaid fluid container to carry said wash and rinse fluid from saidconduit means through said valve to said fluid container.
 7. A milkingplant in accordance with claim 5, comprising a milk measuring device,said milk measuring device comprising four milk meters, said measuringdevice contained in said conduit means and being arranged andconstructed so that each of said milk meters is connected to acorresponding teat cup, said conduit means comprising a separatedischarge line for each of said milk meters, each of said milk metersand each of said separate discharge lines being disposed in said conduitmeans between said rinse jetters and said valve in arrangement wherebywash and rinse fluid from each said jetter flows through and cleans saidmilk meters and said separate discharge lines.
 8. A milking plant inaccordance with claim 7, comprising vacuum generating means for creatinga vacuum which is connected to said milk measuring device, said wash andrinse fluid being caused to move through said wash and rinse system byvacuum produced in said milk measuring device by said vacuum generatingmeans.
 9. A milking plant in accordance with claim 7, comprisingcompressed air supply means connected to each said separate dischargeline in said conduit means in an arrangement so that compressed air canbe introduced into said separate discharge lines to flow through saidconduit means at least up to said valve to displace milk in said conduitmeans from said separate discharge lines and at least up to said valve.10. A milking plant in accordance with claim 9, comprising a computerand sensing means associated with said conduit means for sensing andtransmitting information to said computer when the milking operation insaid milking plant has ceased, said computer being programmed to actuatesaid compressed air supply means to introduce compressed air into saidseparate discharge lines when said milking operation has ceased, and todisplace milk from said separate discharge lines and said conduit meansup to said valve by introducing compressed air to flow therethrough,said computer being operatively connected to said wash and rinse systemand programmed to produce a signal to means that commences theintroduction of wash and rinse fluid via said rinse jetters into saidteat cups to commence a wash and rinse operation of said conduit meansat least up to said valve after milk has been displaced therefrom bysaid compressed air's passage therethrough.
 11. A milking plant inaccordance with claim 10, wherein said sensing means comprises a sensorin said conduit means which senses when milk is no longer being receivedfrom said teat cups in said conduit means, and transmits a signal tosaid computer to such effect.
 12. A milking plant in accordance withclaim 11, whereupon when said computer receives a signal to the effectthat said teat cups are no longer receiving milk from said sensor, saidcomputer transmits a signal to actuate said compressed air supply means,whereby compressed air is introduced into said separate discharge lineto flush milk therefrom.
 13. A milking plant in accordance with claim12, comprising a further sensor which is connected to said conduit meansimmediately before said valve, said further sensor transmitting a signalto said computer that said second discharge line has had the milktherein displaced by the compressed air introduced into said conduitmeans from said compressed air supply means.
 14. A milking plant inaccordance with claim 13, wherein said computer is programmed, uponreceiving information from said further sensor's signal that milk hasbeen displaced from said conduit means up to said valve, to transmit asignal to means provided for controlling said valve causing said valveto switch from a first position wherein milk is passed therethrough tosaid bulk milk cooling tank, to a second position which connects saidconduit means to said wash and rinse system.
 15. A milking plant inaccordance with claim 4, comprising a milking robot for automaticallyconnecting said teat cups to the corresponding teats of a cow's udder.